iPhone 12 touchscreen malfunctioning when charging

Hi,

I have a brand new iPhone 12 and an apple's case for it. When the phone is in the case and plugged in for charging the touchscreen malfunctioning and it is not possible to use the phone. When I charge the phone without a case it works fine. I am using 61W Apple's USB-C Power Adapter (A1718). It very disappointing I assume it has something to do with grounding.